The present invention is directed to a device for pneumatically feeding fiber flocks into a plurality of feeding chutes of fiber processing machines, as well as to a method for pneumatic feeding.
Such devices are known, for example, from German Patent 15 10 370, wherein a distributing line supplies fiber flocks to a plurality of spinning preparation machines and wherein the distributing line ends after a certain number of feeding chutes (dead-end). It is a problem of such distributing lines that it is practically impossible to set the velocity of the transport air such that all feeding chutes connected to the distributing line are fed with fiber flocks in the same way. With too high velocities of the transport air, the supply of fiber flocks to the feeding chutes is insufficient, whereas velocities that are too low entail the risk of clogging, in particular at branches.
German Laid Open 22 42 038 describes a plurality of parallel distributing lines that may simultaneously be charged with different kinds of fiber material, a device being provided at the head of each feeding chute via which, when all feeding lines are operated at the same time, each individual chute roller may be connected with one of the three feeding lines. The respective feeding lines may be charged from different ends so that two or more dead end lines are provided extending in different directions. It is a drawback of this arrangement that each feeding chute has to be connected with two or more distributing lines and that each feeding chute must be provided with a switching means.
From European Patent 0 175 056, a distributing line with a closed end is known, wherein the air velocity is controlled through throttle means. These throttle means are also suitable for blocking the distributor line at any place between two chutes so that two dead end distributing lines may be obtained. This pneumatic transport device for fiber flocks may also be adapted for an oppositely directed flock transport in the transport channel, due to the throttle means being adjustable to both flow directions in the transport channel.